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Re: 3 AXIS Control Board (Complete)

Posted: Tue Sep 14, 2021 9:32 am
by Gary Campbell
Dan Simons wrote: Mon Sep 13, 2021 11:41 pm Gary, quick question as I research and try to learn. When you recommend 350-450 oz-in I was taking that as at the motor and then affected by the gearbox, but is that torque at the gearbox output?
Gearbox output shaft torque is motor torque X reduction. So, for example: 400 ozin motor X 5:1 reduction gives 2000 ozin at output shaft. And since torque is rotary at 1" diameter, to convert to linear force, divide by the pitch radius of the pinion.

Again to use the systems we sell as an example:
~400 ozin motor, 5:1 planetary reduction
20T pinion (1" Pdia)

2000 / .5 = 4000 oz linear force divide by 16 = 250# linear force at the rack.

Note: This is design force, not real world. In the real world steppers are rated by their holding, not moving torque. They are also rated at usually full steps. Setting the drives to 1/8 (1600) steps per rev reduces the available torque to a bit less than 20% or around 50# (at slow speeds. less at higher speeds) and close to half of that again if using 1/10 microstepping